My Merc won't start or run when I have the wrap-around shroud on. Take it off and it starts and runs, soon as I put it back on it dies out...I noticed that there's no type of air cleaner system on the carbs (has the dual-carb set-up). The only space for air to enter is where the shifter cables run in at the port-side front, at the bottom. Is there supposed to be some type of air filtration on it that runs to the above-mentioned space? Also, both of the carbs ended up with a hole corroded into the side of the float bowl in the exact same spot. What causes this? How can I prevent it from happening on my new carbs? Thanks in advance for any help and info! Just got this motor last year and trying to get it running in time for open season on the boat...thanks all!